Towards personalized treatment in juvenile idiopathic arthritis: moving beyond the trial-and-error strategy

The progressive elucidation of juvenile idiopathic arthritis (JIA) pathogenesis has led to growing interest in biomarkers to support diagnosis, subset classification, detection of subclinical inflammation, and/or prediction of disease course and therapeutic response (theragnostic biomarkers). JIA management in clinical practice currently follows a 'trial and error strategy', in which the treatment with the highest response chances is selected mainly based on the clinical phenotype. However, this strategy poses significant challenges, as a substantial proportion of patients fail to achieve sustained remission or experience disease flares. Here, we discuss key determinants of personalized medicine in non-systemic JIA, including ultrasound imaging, synovial fluid and tissue analysis, and circulating biomarkers. In the future, integrating multidimensional data may offer a unique opportunity to identify distinct disease endotypes, anticipate disease trajectory, and, once prospectively validated, inform targeted therapeutic strategies.